Boron nitride (BN) forms bonding configurations similar to carbon. While sharing many of the same robust mechanical and thermal properties of graphite (Cohen et al., Phys. Today, 2010, 63:34-38; Dresselhaus et al., Philos. Trans. R. Soc., 2004, 362:2065-2098), the polar nature of the boron-nitrogen bond in planar (i.e., hexagonal) BN makes BN an optically transparent insulator (Robertson et al., Phys. Rev. B, 1984, 29:2131-2137), with different chemistry on the surface of the hexagonal lattice. As a consequence, BN-based materials are more resistant to oxidation than graphene-based materials (Chen et al., Appl. Phys. Lett., 2004, 84:2430-2432). BN also has enhanced physisorption properties due to the dipolar fields near its surface (Jhi et al., Phys. Rev. B, 2004, 69:245407). BN has been shown to surpass carbon in its ability to store gases such as hydrogen (Borek et al., Langmuir, 1991, 7:2844-2846; Li et al., Nanotechnology, 2013, 24:155603; Ma et al., J. Am. Chem. Soc., 2002, 124:7672-7673; Kim et al., J. Mater. Chem. A, 2013, 1:1014-1017; Weng et al., ACS Nano, 2013, 7:1558-1565; Janik et al., Langmuir, 1994, 10:514-518), and is a very effective and reusable cleanup agent for hydrocarbons (Lei et al., Nat. Commun., 2013, 4:1777). Also, despite its relative chemical inertness, BN surfaces can be functionalized (Ikuno et al., Solid State Commun., 2007, 142:643-646; Lin et al., J. Phys. Chem. C, 2010, 114:17434-17439), allowing for their incorporation into composites (Zhi et al., Adv. Funct. Mater., 2009, 19:1857-1862), as well as their use as scaffolds for nanoparticles in catalysis and other applications (Sainsbury et al., J. Phys. Chem. C, 2007, 111:12992-12999).
Previous synthetic routes for BN-type aerogels and related meso-scale assemblies have included templated growth from existing porous structures such as zeolites (Schlienger et al., Chem. Mater., 2012, 24:88-96), gelation of colloidal BN suspensions (Jung et al., Sci. Rep., 2012, 2:849), and various high temperature reactions of boron and nitrogen containing compounds (Dibandjo et al., J. Eur. Ceram. Soc., 2007, 27:313-317; Paine et al., J. Inorg. Organomet. Polym., 1992, 2:183-195.). Despite a number of promising fields of application, research in this area has been slow due to the often toxic and volatile precursors involved and the limited synthetic routes to high quality BN. Furthermore, these synthesis methods have generally resulted in compounds of mixed BN phases and disordered or turbostratic stacking of planar sheets, corresponding to a crystal structure found in materials where atomic planes are inclined and rotated randomly with respect to one another.
Thus, a need exists for BN-based materials with improved structural quality.